Aromatic polycarbonate composition

ABSTRACT

The present invention relates to a polymer composition comprising the following components: a) 76.6-99.49 mass % of aromatic polycarbonate, b) 0.5-20 mass % of laser direct structuring additive, c) 0-2.4 mass % of rubber like polymer, and d) 0.01-1 mass % of acid and/or acid salt wherein the mass % is calculated relative to the sum of a), b), c) and d). The invention also relates to a moulded part containing this composition, to a circuit carrier containing such moulded part and to a process for producing such circuit carrier.

The present invention relates to a polymer composition comprising apolymer, in particular an aromatic polycarbonate, and a laser directstructuring additive. The invention also relates to a process forproducing such a composition, to a moulded part containing thiscomposition, to a circuit carrier containing such moulded part and to aprocess for producing such circuit carrier.

Polymer compositions comprising a polymer and a laser direct structuring(LDS) additive which additive is capable of being activated by laserradiation and thereby forming elemental metal nuclei, are for exampledescribed in U.S. Pat. No. 2,706,0421 and WO-A-2009024496. Such polymercompositions can advantageously be used in a LDS process for producing anon-conductive part on which conductive tracks are to be formed byirradiating areas of said part with laser radiation to activate theplastic surface at locations where the conductive path is to be situatedand break down the laser direct structuring additive(s) and releasemetal nuclei, and subsequently metalizing the irradiated areas toaccumulate metal on these areas. WO-A-2009024496 describes aromaticpolycarbonate compositions containing a metal compound capable of beingactivated by electromagnetic radiation and thereby forming elementalmetal nuclei and 2, 5-50 mass % of a rubber like polymer, the latterbeing added to reduce degradation of the polycarbonate due to thepresence of such metal compound in aromatic polycarbonate compositions.

It has now been found that the use of such a composition may result inthat the irradiated areas that have been subjected to metallization arenot homogeneously metalized. This is manifested in the existence ofpores in the metalized areas or in that thickness of the metalaccumulation is not uniform over the metalized areas. A pore isgenerated in case metal is not accumulated on the irradiated area duringthe metalizing step. Such pores may be generated in particular in casethe metalizing is effected such that the maximum thickness of theaccumulated metal, in particular copper, is less than 5 μm. Anon-uniform thickness over the metalized area means that metal isaccumulated on each irradiated area, but the thickness of the metalaccumulation on at least one irradiated area is less than the thicknesson the other irradiated areas. Such non-uniform thickness may inparticular develop in case the metalizing is effected such that themaximum thickness of the accumulated metal, in particular copper, ishigher than 5 μm.

The object of the present invention is to provide an aromaticpolycarbonate composition comprising a laser direct structuring additivethat does not show said drawback or shows it to a lesser extent.

This object is achieved in that the polymer composition comprises thefollowing components:

-   -   a) 76.6-99.49 mass % of aromatic polycarbonate,    -   b) 0.5-20 mass % of laser direct structuring additive,    -   c) 0-2.4 mass % of rubber like polymer, and    -   d) 0.01-1 mass % of acid and/or acid salt        wherein the mass % is calculated relative to the sum of        components a), b), c) and d).

It has surprisingly been found that with the composition according tothe invention the metal accumulation, obtained by metallization of theirradiated areas on moulded parts obtained from such a composition, ismore homogeneously over the metalized area, as manifested in theexistence of less pores in the metalized area or in that the thicknessof the metal accumulation is more uniform over the metalized area. Anadditional advantage of the composition according to the invention isthat the average thickness of the metal layer is increased, i.e. moremetal is accumulated on the irradiated area during metallization.

In particular, it has surprisingly been found that the use of an acid oracid salt in a composition comprising aromatic polycarbonate and a laserdirect structuring additive and being substantially free of a rubberlike polymer results in that the accumulation of metal, obtained bymetallization of the irradiated areas of moulded parts obtained fromsuch a composition, can be improved, as manifested by a more homogeneousaccumulation of the metal over the metalized area. An additionaladvantage of the use of an acid or acid salt in such a composition isthat the average thickness of the metalized areas is increased. Thepresent invention therefore also relates to the use of an acid or acidsalt in a composition comprising aromatic polycarbonate and a laserdirect structuring additive and being substantially free of a rubberlike polymer for increasing the homogeneity of metalized areas obtainedby metallization of the irradiated areas of moulded parts obtained fromsuch a composition. As used herein, substantially free of rubber likepolymer means that the amount of rubber like polymer in the compositioncontaining aromatic polycarbonate and laser direct structuring additiveis at most 2.4 mass %, calculated relative to the sum of the amounts ofaromatic polycarbonate, laser direct structuring additive, rubber likepolymer, acid and acid salt. Preferably, the amount of rubber likepolymer is less than 2 mass %, more preferably less than 1.5 mass %,more preferably less than 1 mass % and even more preferably 0 mass % ofrubber like polymer.

The composition contains an acid or an acid salt (component d)). In oneembodiment, the acid or acid salt is an inorganic acid or inorganic acidsalt. In one embodiment, the composition contains a phosphorouscontaining oxy-acid and/or an acid salt thereof. Preferably, thephosphorous containing oxy-acid is a multi-protic phosphorus containingoxy-acid having the general formula H_(m)P_(t)O_(n), where m and n areeach 2 or greater and t is 1 or greater. Examples of such acids include,but are not limited to, acids represented by the following formulas:H₃PO₄, H₃PO₃, and H₃PO₂. Non-limited examples of phosphorus containingoxy-acids are phosphoric acid, phosphorous acid, hypophosphorous acid,hypophosphoric acid, phosphinic acid, phosphonic acid, metaphosphoricacid, hexametaphosphoric acid, thiophosphoric acid, fluorophosphoricacid, difluorophosphoric acid, fluorophosphorous acid,difluorophosphorous acid, fluorohypophosphorous acid, orfluorohypophosphoric acid. In a preferred embodiment of the invention,the composition contains H₃PO₄, H₃PO₃, H₃PO₂ and/or an acid salt ofH₃PO₄, H₃PO₃ or of H₃PO₂. In a more preferred embodiment of theinvention, the composition contains H₃PO₄, H₃PO₃ and/or an acid salt ofH₃PO₄ or of H₃PO₃. Non-limiting examples of acid salts of H₃PO₄ are monozinc phosphate, mono calcium phosphate and mono natrium phosphate.Preferably, component d) is H₃PO₄, H₃PO₃, H₃PO₂ and/or an acid salt ofH₃PO₄, H₃PO₃ or of H₃PO₂ or a mixture thereof. More preferably,component d) is H₃PO₄, H₃PO₃, and/or the Zn salt of H₃PO₄ or of H₃PO₃ ora mixture thereof.

The composition contains rubber like polymer in an amount of from 0 upto and including 2.4 mass %. Preferably, the amount of rubber likepolymer is less than 2 mass %, more preferably less than 1.5 mass %,more preferably less than 1 mass % and even more preferably 0 mass % ofrubber like polymer. In a preferred embodiment of the present invention,the composition does not contain rubber like polymer. The rubber-likepolymer is or contains an elastomeric (i.e. rubbery) polymer havingpreferably a T_(g) less than about 10° C. Examples of elastomericpolymers include polyisoprene; butadiene based rubbers likepolybutadiene, styrene-butadiene random copolymer and block copolymer,hydrogenates of said block copolymers, acrylonitrile-butadiene copolymerand butadiene-isoprene copolymer; acrylate based rubbers likeethylene-methacrylate and ethylene-butylacrylate, acrylateester-butadiene copolymers, for example acrylic elastomeric polymerssuch as butylacrylate-butadiene copolymer; siloxane based rubbers likepolyorganosiloxanes such as for example polydimethylsiloxane,polymethylphenylsiloxane and dimethyl-diphenylsiloxane copolymer; andother elastomeric polymers like ethylene-propylene random copolymer andblock copolymer, copolymers of ethylene and α-olefins, copolymers ofethylene and aliphatic vinyl such as ethylene-vinyl acetate, andethylene-propylene non-conjugated diene terpolymers such asethylene-propylene-hexadiene copolymer, butylene-isoprene copolymer, andchlorinated polyethylene.

The polycarbonate composition according to the invention contains interalia from 76.6 up to 99.49 mass % of aromatic polycarbonate, preferablyfrom 77 up to 98.99 mass %, preferably from 87.5 up to 96.99 mass %,more preferably from 88 up to 95.99 mass % of aromatic polycarbonate,even more preferably from 89 up to 94.99 mass % of aromaticpolycarbonate. Suitable aromatic polycarbonates are polycarbonates madefrom at least a divalent phenol and a carbonate precursor, for exampleby means of the commonly known interfacial polymerization process or themelt polymerisation method. Suitable divalent phenols that may beapplied are compounds having one or more aromatic rings that contain twohydroxy groups, each of which is directly linked to a carbon atomforming part of an aromatic ring. Examples of such compounds are4,4′-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A),2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis-(3-chloro-4-hydroxyphenyl)-propane,2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,2,4-bis-(4-hydroxyphenyl)-2-methylbutane,2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane,4,4-bis(4-hydroxyphenyl)heptane,bis-(3,5-dimethyl-4-hydroxyphenyl)-methane,1,1-bis-(4-hydroxyphenyl)-cyclohexane,1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane,2,2-(3,5,3′,5′-tetrachloro-4,4′-dihydroxydiphenyl)propane,2,2-(3,5,3′,5′-tetrabromo-4,4′-dihydroxydiphenyl)propane,(3,3′-dichloro-4,4′-dihydroxyphenyl)methane,bis-(3,5-dimethyl-4-hydroxyphenyl)-sulphon, bis-4-hydroxyphenylsulphon,bis-4-hydroxyphenylsulphide.

The carbonate precursor may be a carbonyl halogenide, a halogen formateor carbonate ester. Examples of carbonyl halogenides are carbonylchloride and carbonyl bromide. Examples of suitable halogen formates arebis-halogen formates of divalent phenols such as hydroquinone or ofglycols such as ethylene glycol. Examples of suitable carbonate estersare diphenyl carbonate, di(chlorophenyl)carbonate,di(bromophenyl)carbonate, di(alkylphenyl)carbonate, phenyltolylcarbonateand the like and mixtures thereof. Although other carbonate precursorsmay also be used, it is preferred to use the carbonyl halogenides and inparticular carbonylchloride, also known as phosgene.

The aromatic polycarbonates in the composition according to theinvention may be prepared using a catalyst, an acid acceptor and acompound for controlling the molecular mass.

Examples of catalysts are tertiary amines such as triethylamine,tripropylamine and N,N-dimethylaniline, quaternary ammonium compoundssuch as tetraethylammoniumbromide and quaternary phosphonium compoundssuch as methyltriphenylfosfoniumbromide.

Examples of organic acid acceptors are pyridine, triethylamine,dimethylaniline and so forth. Examples of inorganic acid acceptors arehydroxides, carbonates, bicarbonates and phosphates of an alkali metalor earth alkali metal.

Examples of compounds for controlling the molecular mass are monovalentphenols such as phenol, p-alkylphenols and para-bromophenol andsecondary amines.

Such polycarbonates, their preparation and properties are described indetail in for example Encycl. Polym. Sci. Eng., 11, p. 648-718 (Wiley,New York, 1988) and in Kunststoff Handbuch, 3/1, p. 117-297 (HauserVerlag, Muenchen, 1992).

The composition according to the invention preferably contains apolycarbonate derived from bisphenol A and phosgene and optionally minoramounts of other compounds having one, two or more than two reactivegroups as comonomers, for instance for controlling the melt viscosity.

The polycarbonate composition contains a laser direct structuringadditive (component b)) that enables the composition to be used in alaser direct structuring (LDS) process. In a LDS process, a laser beamexposes the LDS additive to place it at the surface of the polycarbonatecomposition and to release metal nuclei from the LDS additive. As such,the LDS additive is selected such that, upon exposure to a laser beam,metal atoms are activated and exposed and in areas not exposed by thelaser beam, no metal atoms are exposed.

Component b) is capable of being activated by laser radiation andthereby forming elemental metal nuclei within the polycarbonatecomposition. The component b) is a metal-containing (inorganic ororganic) compound which as a consequence of absorption of laserradiation liberates metal in elemental form. It is also possible thatthe radiation is not directly absorbed by the metal-containing compound,but is absorbed by other substances which then transfer the absorbedenergy to the metal-containing compound and thus bring about theliberation of elemental metal. The laser radiation may be UV light(wavelength from 100 to 400 nm), visible light (wavelength from 400 to800 nm), or infrared light (wavelength from 800 to 25 000 nm). Otherpreferred forms of radiation are X-rays, gamma rays, and particle beams(electron beams, [alpha]-particle beams, and [beta]-particle beams). Thelaser radiation is preferably infrared light radiation, more preferablywith a wavelength of 1064 nm. Examples of LDS additives useful in thepresent invention include for example copper chromium oxide spinel,copper molybdenum oxide spinel, a copper salt, such as for examplecopper hydroxide phosphate; copper phosphate and copper sulphate.

The component b) capable of being activated by laser radiation ispreferably comprised of electrically non-conductivehigh-thermal-stability organic or inorganic metal compounds which arepreferably insoluble and stable in aqueous acidic or alkaline metalizingbaths. Particularly suitable compounds are those which absorb a verylarge proportion of the light at the wavelength of the incident light.Compounds of this type are described in EP-A-1 274 288. Preference isgiven here to compounds of metals of the d and f group of the PeriodicTable of the Elements with non-metals. The metal-containing compoundsare particularly preferably metal oxides, in particular oxides of thed-metals of the Periodic Table of the Elements. Higher metal oxideswhich contain at least two different kinds of cations and have a spinelstructure or spinel-related structure, and which remain unchanged innon-irradiated areas of the moulded part that contains the compositionof the present invention are particularly suitable. In one particularlypreferred embodiment of the invention, the higher oxides are spinets, inparticular copper-containing spinets, such as CuCr₂O₄. Suitablecopper-containing spinets are commercially available, an example beingPK 3095 from Ferro (DE) or 34E23 or 34E30 from Johnson Matthey (DE).Copper oxides of the formula CuO or Cu₂0 are also particularly suitable,and use is preferably made here of nanoparticles, such as NANOARC®Copper Oxide from Nanophase Technologies Corporation, Illinois, USA. Inanother particularly preferred embodiment of the invention, the higherspinel oxide is a manganese-containing spinel. As will be understood bya man skilled in the art also a mixture of metal compounds can be used.

Preferably, the metal compound is represented by the chemical formulaAB₂O₄ or B(AB)O₄. The A component of the formulas is a metal cationhaving a valence of 2 and is selected from the group consisting ofcadmium, zinc, copper, cobalt, magnesium, tin, titanium, iron, aluminum,nickel, manganese, chromium, and combinations of two or more of these.The B component of the formulas is a metal cation having a valence of 3and is selected from the group consisting of cadmium, manganese, nickel,zinc, copper, cobalt, magnesium, tin, titanium, iron, aluminum,chromium, and combinations of two or more of these.

The polymer compositions of the invention have dispersed therein metalcompound(s), where the metal compound preferably comprises two or moremetal oxide cluster configurations within a definable crystal formation.The overall crystal formation, when in an ideal (i.e., non-contaminated,non-derivative) state, has the following general formula:

AB₂O₄,

where

-   -   i. A is selected from the group consisting of cadmium, zinc,        copper, cobalt, magnesium, tin, titanium, iron, aluminum,        nickel, manganese, chromium, and combinations thereof, which        provides the primary cation component of a first metal oxide        cluster (“metal oxide cluster 1”) typically a tetrahedral        structure,    -   ii. B is selected f from the group consisting of cadmium,        manganese, nickel, zinc, copper, cobalt, magnesium, tin,        titanium, iron, aluminum, chromium, and combinations thereof and        which provides the primary cation component of a second metal        oxide cluster (“metal oxide cluster 2”) typically an octahedral        structure,    -   iii. where within the above groups A or B, any metal cation        having a possible valence of 2 can be used as an “A”, and any        metal cation having a possible valence of 3 can be used as a        “B”,    -   iv. where the geometric configuration of “metal oxide cluster 1”        (typically a tetrahedral structure) is different from the        geometric configuration of “metal oxide cluster 2” (typically an        octahedral structure),    -   v. where a metal cation from A and B can be used as the metal        cation of “metal oxide cluster 2” (typically the octahedral        structure), as in the case of an ‘inverse’ spinel-type crystal        structure,    -   vi. where O is primarily, if not exclusively, oxygen; and    -   vii. where the “metal oxide cluster 1” and “metal oxide cluster        2” together provide a singular identifiable crystal type        structure having heightened susceptibility to electromagnetic        radiation.

The concentration of these components b) present in the composition ofthe present invention is from 0.5 up to 20 mass %, preferably from 1 upto 20 mass %, preferably from 3 up to 10 mass %, more preferably from 4up to 10 mass %, and particularly preferably from 5 up to 10 mass %.

In a preferred embodiment, the composition according to the inventioncontains a) 77-98.99 mass % of aromatic polycarbonate, b) 1-20 mass % oflaser direct structuring additive, c) 0-2 mass % of rubber like polymer,and d) 0.01-1 mass % of acid and/or acid salt, relative to the sum ofa), b), c) and d). In another preferred embodiment, the compositionaccording to the invention contains a) 87.5-96.99 mass % of aromaticpolycarbonate, b) 3-10 mass % of laser direct structuring additive, c)0-1.5 mass % of rubber like polymer, and d) 0.01-1 mass % of acid and/oracid salt. In another preferred embodiment, the composition according tothe invention contains a) 88-95.99 mass % of aromatic polycarbonate, b)4-10 mass % of laser direct structuring additive,

c) 0-1 mass % of rubber like polymer, and d) 0.01-1 mass % of acid oracid salt. In still another preferred embodiment, the compositionaccording to the invention contains a) 89-94.99 mass % of aromaticpolycarbonate, b) 5-10 mass % of laser direct structuring additive, c) 0mass % of rubber like polymer, and d) 0.01-1 mass % of acid and/or acidsalt.

The polycarbonate composition according to the invention may furthercomprise from 0 up to 25 mass % of one or more other additives, relativeto the total weight of components a), b), c) and d). These include thecustomary additives such as stabilizers against thermal orthermo-oxidative degradation, stabilizers against hydrolyticdegradation, stabilizers against degradation from light, in particularUV light, and/or photo-oxidative degradation, impact modifiers,processing aids such as release agents and lubricants, colorants such aspigments and dyes, fillers including minerals such as wollastonite oraluminium silicates. Suitable examples of such additives and theircustomary amounts are stated in the aforementioned Kunststoff Handbuch,3/1.

The polymer composition may further comprise reinforcing agents, such asglass fibres. The polymer composition may comprise between 0 and 30 wt %glass fibres, relative to the sum of a), b), c) and d), preferablybetween 0 and 20 wt %.

The components b), c) (if present) and d) and optionally other additivesas described above, and also any other additives and reinforcing agentsmay be introduced into the aromatic polycarbonate by means of suitablemixing devices such as single-screw or twin-screw extruders, preferablya twin-screw extruder is used. Preferably, aromatic polycarbonatepellets are introduced into the extruder together with at leastcomponents b) and d) and extruded, then quenched in a water bath andthen pelletized. The invention therefore further relates to a processfor producing an aromatic polycarbonate composition according to thepresent invention by melt mixing components a), b), d) and optionally c)and other (particulate) additives and reinforcing agents.

The invention further relates to moulded parts that contains thepolycarbonate composition according to the present invention. Theinvention relates in particular to a moulded part produced by injectionmoulding of the composition according to the invention. The inventionfurther also relates to an article, in particular a circuit carrier,that contains a moulded part produced from the composition according tothe invention. In one embodiment, such a circuit carrier is used forproducing an antenna.

The invention further relates to a process for producing such a circuitcarrier which process comprises the steps of providing a moulded partthat contains the polycarbonate composition according to the presentinvention, irradiating areas of said part on which conductive tracks areto be formed with laser radiation to break down the LDS additive b) andreleasing metal nuclei, and subsequently metallizing the irradiatedareas. In a preferred embodiment, laser is used to simultaneouslyrelease metal nuclei and effect ablation of the part while forming anadhesion-promoting surface. This provides a simple means to achieveexcellent adhesive strength of the deposited metallic conductor tracks.The wavelength of the laser is advantageously 248 nm, 308 nm, 355 nm,532 nm, 1064 nm or of even 10600 nm. The deposition of further metalonto the metal nuclei generated by laser radiation preferably takesplace via plating processes. Said metallizing is preferably performed byimmersing the moulded part in at least one electroless plating bath toform electrically conductive pathways on the irradiated areas of themoulded part. Non-limiting examples of electroless plating processes area copper plating process, gold plating process, nickel plating process,silver plating, zinc plating and tin plating.

The invention will now be elucidated with reference to the followingexamples and comparative experiments.

COMPARATIVE EXPERIMENTS A-F AND EXAMPLES 1-4

The compositions of Comparative Experiments (CEx) A-F and of Examples(Ex) 1-4 were prepared from the components as given in Table 1.

All samples were extruded on a co-rotating twin screw extruder at atemperature of 280° C. according the compositions as given in Table 2 or3. The extrudate was granulated and the collected granulate wasinjection moulded into plaques of 70*50*2 mm using a melt temperature of290° C. to 310° C. depending on the viscosity of the material for thesamples of Table 2 and using a melt temperature of 250° C. to 270° C.depending on the viscosity of the material for the samples of Table 3.

Plating performance was judged after laser activation on the injectionmolded plaques and a subsequent plating procedure in an electrolesscopper plating bath. Laser activation was done on a LPKF Microline 3Dlaser, using a laser wavelength of 1064 nm and a hatch size of 55 μm ata speed 4 m/s. In order to investigate the laser processing window, amatrix of in total 3×6 settings were used, varying the laser frequencyover 3 levels from 60 kHz to 100 kHz and the laser power over 6 levelsfrom 4 W to 10 W. Laser activated parts were cleaned to remove any laserdebris and subsequently the activated areas were metalized in aMacDermid M-Copper 85 plating bath for about 1 hour. As a result, theinjection moulded plaque contains 18 copper plated areas with an averagethickness less than 5 μm. The plating performance was judged accordingto the average thickness and homogeneity (closed or porous) of thecopper layer for the 18 copper plated areas. The homogeneity was visiblejudged.

Table 2 shows the compositions and results of Comparative Experiments(CEx) A to B and Examples (Ex) 1 to 4. Quality of the copper layer isgiven by the average copper thickness and level of homogeneity of alllaser setting areas. The level of homogeneity is expressed by thepercentage of laser setting areas that show a completely closed copperlayer (no porosity).

If a laser setting area is completely covered by a copper layer, thisarea is considered to be homogenous. If an area shows one or more poresin the copper layer, this area is considered to be inhomogeneous.

The homogeneity of a sample is defined as the number of homogeneousareas devided by the total number of areas (homogeneous andinhomogenous) of the sample. For example, in case only 9 of the 18copper plated areas show a completely closed copper layer and the other9 show porosity, the homogeneity is considered to be 50%. The resultsshow that the plating performance of Examples 1 to 4 is significantlyimproved to Comparative Experiments A to B, since the copper thicknessis increased with more than 100% and all laser setting areas show ahomogeneous layer structure (100% homogeneity).

TABLE 1 Material Type Supplier Polycarbonate LVN (ISO 1628/4) = 43 ml/gDSM (PC MFI = 23) Polycarbonate LVN (ISO 1628/4) = 51 ml/g DSM (PC MFI =8) Polycarbonate LVN (ISO 1628/4) = 60 ml/g DSM (PC MFI = 3) Moldrelease Loxiol P861/3.5 Cognis (MRA) Heat Stabilizer (HS) Irgafos 168Ciba CuCr₂O₄ Black 1G Shepherd Company MZP Z 21-82 (Mono Zinc BudenheimPhosphate) ABS Santac AT-05 Mitsui Germany MBS KaneAce M511 Kaneka

TABLE 2 Sample CEx Units A Ex 1 Ex 2 Ex 3 CEx B Ex 4 Com- ponents PC %91.45 91.25 (MFI = 23) PC % 91.40 91.05 (MFI = 8) PC % 91.45 91.25 (MFI= 3) CuCr₂O₄ % 8 8 8 8 8 8 MZP % 0.2 0.05 0.4 0.2 MRA + % 0.55 0.55 0.550.55 0.55 0.55 HS Quality of Copper layer Thickness μm 0.96 2.49 2.853.14 1.44 3.81 Homo- % 0 100 100 100 33 100 geneity

TABLE 3 Sample Units CEx C CEx D CEx E CEx F Components PC (MFI = 4) %56.45 56.25 56.45 71.25 ABS % 30 30 35 15 MBS % 5 5 CuCr₂O₄ % 8 8 8 8MZP % 0.2 0.2 MRA + HS % 0.55 0.55 0.55 0.55 Quality of Copper layerThickness μm 3.4 3.6 3.1 4.3 Homogeneity % 17 17 0 17

The % in table 2 and 3 relate to the wt % of components relative to thetotal of the composition. From the comparative experiments C-F it isclear that the presence of rubber-like polymer such as ABS and MBS insubstantial amounts, results in that accumulation of metal over themetalized areas is not homogeneously. This also holds in case smallamounts of rubber like polymer is present (CEx F). Adding MZP (acidsalt) to a composition containing rubber like polymer does not result inan improvement of the homogeneity (CEx D and F). Compositions containingpolycarbonate, LDS additive, acid salt but not a rubber like polymer(CEx A and B) also suffer from low homogeneity of the metal accumulationand in addition the average thickness of the metal accumulation is low.Only the compositions according to the invention

(Ex 1, 2, 3 and 4) show a very good homogeneity and in addition asufficient average thickness of the accumulated metal.

1. Polymer composition comprising the following components: a)76.6-99.49 mass % of aromatic polycarbonate, b) 0.5-20 mass % of laserdirect structuring additive, c) 0-2.4 mass % of rubber like polymer, andd) 0.01-1 mass % of acid and/or acid salt wherein the mass % iscalculated relative to the sum of components a), b), c) and d). 2.Polymer composition according to claim 1, wherein the compositionfurther comprises from 0 up to 25 mass % of additives, wherein theamount is relative to the sum of components a), b), c) and d). 3.Polymer composition according to claim 1, wherein the compositioncomprises a copper containing spinel as laser direct structuringadditive.
 4. Polymer composition according to claim 1, wherein thecomposition comprises CuCr₂O₄ as laser direct structuring additive. 5.Polymer composition according to claim 1, wherein the composition doesnot contain a rubber like polymer.
 6. Polymer composition according toclaim 1, wherein the acid is an inorganic acid or inorganic acid salt.7. Polymer composition according to claim 1, wherein the compositioncontains a phosphorous containing oxy-acid and/or an acid salt thereof.8. Polymer composition according to claim 1, wherein the compositioncontains H₃P0₄, H₃P0₃ and/or an acid salt of H₃P0₄ or of H₃P0₃. 9.Moulded part that contains the polycarbonate composition according toclaim
 1. 10. A circuit carrier that contains at least a moulded partaccording to claim
 9. 11. A process for producing a circuit carrieraccording to claim 10, irradiating areas of said part on whichconductive tracks are to be formed with laser radiation to break downthe LDS additive b) and releasing metal nuclei, and subsequentlymetallizing the irradiated areas.
 12. Use of an acid or acid salt in acomposition comprising aromatic polycarbonate and a laser directstructuring additive and being substantially free of a rubber likepolymer for increasing the homogeneity of metalized areas obtained bymetallization of the irradiated areas of moulded parts obtained fromsuch a composition.
 13. Use according to claim 12, wherein d) the acidand/or acid salt is added in an amount of 0.01-1 mass % to a compositioncomprising a) 76.6-99.49 mass % of aromatic polycarbonate, b) 0.5-20mass % of a laser direct structuring additive and c) 0-2.4 mass % ofrubber like polymer, wherein the mass % is calculated relative to thesum of the components a), b), c) and d.
 14. Use according to claim 12,wherein the composition does not contain a rubber like polymer.
 15. Useaccording to claim 12, wherein the acid is an inorganic acid orinorganic acid salt.
 16. Use according to claim 12, wherein thecomposition contains a phosphorous containing oxy-acid and/or an acidsalt thereof.
 17. Use according to claim 12, wherein the compositioncontains H₃PO₄, H₃PO₃ and/or an acid salt of H₃PO₄ or of H₃PO₃.